No matter how flexible a template system is, it's always possible to add to it with more templates, unless the template system has a finite number of possibilities. Even then, someone somewhere will want to make one that adds a new element to increase the possibilities.
The best example of this effect is in the proliferation of classes in Rolemaster, D20, and Palladium games.
And, looking at the templates in DFRPG, there is plenty of room for them to be expanded and varied.
So, yes, it's likely that eventually, additional templates will become useful.
And, based upon Wraith808's answer, it's apparent the design team is going to do more.